排序方式: 共有76条查询结果,搜索用时 15 毫秒
71.
Abstract
The title compound (C5Me5)2Th[-N=C(Ph)(tpy)]2 (1) (Ph=C6H5, tpy=2,2′:6′,2″-terpyridine) was synthesized and characterized by NMR spectroscopy, elemental analysis, and X-ray crystallography. This system represents the first example of an actinide complex featuring ketimide ligands with both a phenyl group and a terpyridyl group. The complex crystallizes in the monoclinic space group P21/c with unit cell parameters a = 10.7037(6) ?, b = 32.0735(16) ?, c = 34.6506(18) ?, β = 90.127(3)°, V = 11895.7(11) ?3, Z = 8, D calc = 1.406 Mg/m3. The thorium(IV) complex adopts a pseudo-tetrahedral geometry, with the two ketimide ligands occupying the plane bisecting the metallocene unit. Structural comparisons of the title complex are made with related metallocene thorium(IV) bis(ketimide) derivatives. 相似文献72.
Schelter EJ Veauthier JM Thompson JD Scott BL John KD Morris DE Kiplinger JL 《Journal of the American Chemical Society》2006,128(7):2198-2199
Novel 4f-5f complexes of U(IV) and Th(IV) with Yb have been prepared using a terpyridyl-functionalized ketimide linking group. These 4f-5f heterotrimetallic complexes (C5Me5)2An[-N=C(CH2C6H5)(tpyYb(C5Me5)2)]2 (where An = Th, U) exist in Yb(II/III) valence equilibria and exhibit rich electrochemical behavior consistent with electronic coupling between the actinide and Yb(II/III)tpy*- moieties. The magnetic response of the uranium complex, studied qualitatively using a subtraction method, is indicative of a coupled magnetic state between the U(IV) and Yb(III)tpy*- groups at low temperatures. Both the electrochemical and magnetic data are in agreement and are consistent with differences in participation of the actinide valence orbitals in the ketimide bonding. 相似文献
73.
A Rare Tetranuclear Thorium(IV) μ4‐Oxo Cluster and Dinuclear Thorium(IV) Complex Assembled by Carbon–Oxygen Bond Activation of 1,2‐Dimethoxyethane (DME) 下载免费PDF全文
Dr. Nicholas E. Travia Dr. Brian L. Scott Dr. Jaqueline L. Kiplinger 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(51):16846-16852
The synthesis and X‐ray crystal structure of two new multinuclear thorium complexes are reported. The tetranuclear μ4‐oxo cluster complex Th4(μ4‐O)(μ‐Cl)2I6[κ2(O,O’)‐μ‐O(CH2)2OCH3]6 and the dinuclear complex Th2I5[κ2(O,O’)‐μ‐O(CH2)2OCH3]3(DME) (DME=dimethoxyethane) are formed by C?O bond activation of 1,2‐dimethoxyethane (DME) mediated by thorium iodide complexes. 相似文献
74.
Veauthier JM Schelter EJ Kuehl CJ Clark AE Scott BL Morris DE Martin RL Thompson JD Kiplinger JL John KD 《Inorganic chemistry》2005,44(16):5911-5920
A new N-heterocyclic complex of ytterbocene (Cp(2)Yb(II), Cp = C(5)Me(5)) has been prepared by the addition of 4'-cyano-2,2':6',2' '-terpyridine (tpyCN) to Cp(2)Yb(II)(OEt(2)) in toluene to give a dark blue species designated as Cp(2)Yb(tpyCN). The effect of the electron-withdrawing group (-CN) on the redox potentials of the charge-transfer form of this complex [in which an electron is transferred from the f(14) metal center to the lowest unoccupied (pi) molecular orbital of the tpyCN ligand to give a 4f(13)-pi(1) electronic configuration] has been quantified by cyclic voltammetry. The tpyCN ligand stabilizes this configuration by 60 mV more than that in the unsubstituted tpy ligand complex and by 110 mV more than that in the unsubstituted bpy ligand complex. Magnetic susceptibility measurements corroborate the enhanced stabilization of the 4f(13)-pi(1) configuration by the substituted terpyridyl ligand complex. Furthermore, the temperature dependence of the magnetic data is most consistent with a thermally induced valence tautomeric equilibrium between this paramagnetic 4f(13)-pi(1) form that dominates near room temperature and the diamagnetic 4f(14)-pi(0) form that dominates at low temperature. Differing coordination modes for the tpyCN ligand to the ytterbocene center have also been confirmed by isolation and X-ray crystallographic characterization of complexes binding through either the cyano nitrogen of tpyCN or the three terpyridyl nitrogen atoms of tpyCN. 相似文献
75.
Crepin C Broquier M Dubost H Galaup JP Le Gouet JL Ortega JM 《Physical review letters》2000,85(5):964-967
Infrared picosecond accumulated photon echo experiments have been performed for the first time, using the Orsay Free Electron Laser, on the v = 0-->v = 1 transition of CO in solid nitrogen. The vibrational dephasing time is found to be exceptionally long ( T2>/=120 ns) at low temperature. The analysis of the observed spectral diffusion leads one to assume different energy transfer mechanisms depending on the CO concentration. 相似文献
76.
Carreno MC Garcia Ruano JL Urbano A Remor CZ Arroyo Y 《The Journal of organic chemistry》2000,65(2):453-458
Diels-Alder reactions of (SS)-2-(2'-methoxynaphthylsulfinyl)-1, 4-benzoquinone (1b), 2-(p-methoxyphenylsulfinyl)-1,4-benzoquinone (1c), and 2-(p-nitrophenylsulfinyl)-1,4-benzoquinone (1d) with cyclopentadiene are reported. These cycloadditions allowed the highly chemo- and stereoselective formation of both diastereoisomeric endo-adducts resulting from reaction on the unsubstituted double bond C(5)-C(6) of quinones working under thermal and Eu(fod)(3)- or BF(3).OEt(2)-catalyzed conditions. The synthesis of endo-adduct [4aS,5S,8R,8aR,SS]-9d resulting from cycloaddition on the substituted C(2)-C(3) double bond was achieved in a chemo- and diastereoselective way from quinone 1d in the presence of ZnBr(2). The reactivity and selectivity of the process proved to be dependent on the electron density of the arylsulfinyl group. 相似文献